This invention pertains to a apparatus, which remove a sulfur dioxide and a nitrogen oxide, which are generated by combustion of coal or oil. This invention also relates to a boiler system with such a apparatus.
There has been used a boiler system in which a dust in a flue gas is removed by an electrostatic precipitator, the flue gas is cooled through a cooler tower, in a irradiation duct an electron beam is irradiated normal direction to the gas flow, and an ammonium is supplied. Then a mixture of an ammonium sulfate and an ammonium nitride is produced. As a results the flue gas is cleaned. These systems are disclosed in a Japanese patent application: H8-16433.
In the prior arts the electron beam with a 800 keV of beam energy is irradiated normal direction to the flue gas flow. As a scattering cross section between the electron beam with 800 keV of beam energy and the flue gas is small, the flue gas that flow irradiation window side is not absorb sufficiently the electron energy and then pass through the irradiation duct. The scattering cross section between the electron and the flue gas is large, only at the anti-window side, as the electron beam have lost its initial energy through the passage into the flue gas. Therefore, only in the flue gas, which pass through the anti-window side, sulfur dioxide and nitride oxide is removed sufficiently.
For the conventional apparatus, the electron beam with high energy irradiate metal parts and high intensity X-ray is generated. Therefore a close X-ray shield is necessary and most of the electron energy is not used for the reaction. It is also problem that a high voltage power source and an insulator are very expensive and unreliable. It is also other problem that when the beam current is increased, the irradiation entrance window become very hot.
It is a purpose of the invention to provide a charged particle beam treatment apparatus, in which adverse effect of the small collision cross-section between flue gas and the electron beam, a high temperature window, and too high acceleration voltage are improved. The apparatus is also suitable for obtaining a low cost apparatus with improved de-sulfate and de-nitride. It is also the purpose of this invention to offer a boiler system which emit flue gas with a little sulfur dioxide and nitride oxide.
The electron beam treatment apparatus of the first embodiment of this invention comprises: an irradiation duct, introduction entrances for the electron beam and an ammonium, wherein an electric field that deflect the electron beam is introduced into the irradiation duct.
The electron beam treatment apparatus of the second embodiment of this invention comprises: an electron source, an irradiation duct, a window for the electron beam inlet, and an ammonium introduction entrance, wherein said window is made of SiC ceramics or an aluminum alloy film with a non-corrosion coating.
The electron beam treatment apparatus of the third embodiment of this invention comprises: an electron source, an irradiation duct, an introduction entrance for the electron beam inlet, and an ammonium introduction entrance, wherein said electron beam source have a cathode, a convergent electrode, and form a crossover at the electron beam introduction entrance.